Modern day automotive vehicles typically include a drive power source, such as an internal combustion engine or an electric motor, connected to a transmission. The transmission carries the torque output from the drive power source and applies it to the driving wheel through a differential unit. A differential drive pinion is positioned between an output shaft of the transmission and an input shaft of the differential unit so as to output the inputted power.
The differential drive pinions are rotatively supported by bearings which must be lubricated to ensure proper power transmission. In order to restrain the flow of a lubricating fluid flowing through the hollow interior of the differential drive pinion, a plug is inserted therein. However, the previously known plugs require multiple manufacturing steps which increases the overall costs associated with the vehicle. Moreover, the overall price of the plugs is increased due to the increase in the required maintenance of the tool and die used in the production of the plugs.
With references to FIG. 6A through 6C a previously known plug A is provided with a plate section B and a rim section C. The plug A is press fit within the passes of the differential drive pinion and is retained by the engagement between the exterior of the rim B and the interior surface of the differential drive pinion, as seen in FIG. 6B. A plurality of aperture D are formed in the plate section B of the plug A so as to allow lubricating fluid to flow through the plug A.
As seen in FIG. 6B, the previously known plug A is formed by stamping a blank E, as seen in FIG. 6C, from a sheet of metallic material (not shown). Next, the blank E is required to undergo a drilling operation in which the plurality of apertures 16 that are formed in the blank E. Then, an edge of the blank E is bent to form the rim C that surrounds the plate section B. Accordingly, the previously known plugs A require three separate operations which increases the overall cost of the plug and the vehicle.
Due to the required shape of the blank E, the tool and die required for the manufacturing thereof is required to undergo significantly increased maintenance in order to provide the required precision. However, the increase in the required maintenance of the tool and die increases the overall manufacturing time and as such, the overall cost of the part and the automotive vehicle.
A further disadvantage of the previously known plugs A is the amount of material required for formation of the blank E compared to the overall diameter of the finalized plug 10. As the rim C extends the entire perimeter of the plate B the diameter of the blank E is larger than the diameter of the plate B by the length of the rim C. Accordingly, the overall cost of the previously known plugs is increased due to the large size of the blank E. Specifically, due to the specific circular shape of the blanks E, the number of blanks E that can be formed from a sheet is reduced.
Further still, as the shape of the plug A is formed by drawing the blank E so as to form the rim C, the plurality of apertures D are required to be provided within the interior of the plate B. As such, during periods of non-rotation of the differential drive pinion a portion of the lubricating fluid flowing through the passageway is blocked by the plate B due to the positioning of the apertures being spaced from the interior surface of the passage. Even during conditions of rotation of the differential drive pinion, a portion of the lubricating fluid is blocked from flowing to the bearings due to the positioning of the aperture D spaced apart from the interior surface of the passageway, as clearly seen in FIG. 6B.
Thus, there exists a need in the art to provide a plug for restricting the flow of a fluid within a passageway of a differential drive pinion that reduces costs, and weight by decreasing the required daily maintenance and the overall size of the blank used to form the plug, and which prevents the blockage of a portion of the lubricating fluid flow from flowing to the bearings due to the positioning of the apertures that are spaced apart from the interior surface of the passageway of the differential drive pinion.